Bicycles have existed for many years throughout serving as transportation and sporting means. Over the great time span since their inception, the technology has evolved with numerous designs and advancements predominantly geared toward addressing rider comfort. With the initial designs from many years ago comprising a single speed power transmission mechanism often requiring the rider to either exert undue effort on the pedals or have to alternate the pedals at an uncomfortably high rate to achieve desired riding speed, a need was recognized for multiple powertrain ratios to facilitate acceptable operator pedaling rates and efforts. A variety of designs consequently evolved where additional power transmission sprockets of various number of teeth but equal pitch were added in the axial directions of the pedals mechanism as well as power transmission rear wheel to facilitate a combination of front and rear power transmission ratios resulting in optimal settings based on desired vehicle speeds, road conditions, operator biometrics and preference. This innovation was facilitated by the de-facto standard four bar linkage mechanism based derailleur assembly used to this very day to alternate drive sprockets through properly positioning the drive chain thereto as well as compensate for resultant varying chain lengths through an integral spring loaded chain tensioning mechanism. This capability was facilitated by two cable tensioning apparatuses, one for rear sprockets and another for the fronts. With one end of each cable apparatus connected to the derailleur chain positioning mechanism and the other end to an operator actuation mechanism typically comprising a lever assembly, these apparatuses granted the operator the ability to alternate the chain position in the axial position for proper alignment and thereby engagement of selected rear and front drive sprockets in order to achieve optimal power transmission ratio settings. Advancements in the actuation mechanism included indexing capability of the operator lever assembly so that the actuation of the derailleur mechanism takes place in an indexing fashion consistently properly aligning the chain with desired sprocket thereof rather than one continuous motion requiring the operator to guess the proper chain position often leading to positioning errors.
As the technology to provide the desired function of automating the manual shift operation of the bicycle has existed for years, numerous attempts have been made to provide a robust yet commercially successful product. Some were attempts sacrificing robust componentry for cost, tight packaging and commerciality, in the process adding extraneous components such as springs and levers to prevent premature failure, while others were based on complex mathematical or fixed criteria based on “One for All” approaches. On the fundamental level most failed to recognize the basic limitation of the legacy shifter mechanism inability to shift less chain motion. With such conditions arising during coasting, braking or downhill descent where the operator ceases to operate the pedals, these numerous attempts managed to ultimately achieve varying levels of success but uniformly fell short of meeting widespread commercial acceptance. On the fundamental level, most of these offerings had in common the failure to recognize that acceptance of these various designs ultimately boiled down to adaptability by a user population widespread in biometrics, endurance, strength and size.
The inventor hereby discloses a versatile automatic bicycle shifter making use of servo motors, a robust microprocessor based control system making use of various speed, chain movement and road inclination sensors, a highly adaptable user interface making use of a set of operator predefined and in real time adjustable criteria, and additionally making use of a chain driver apparatus ensuring forward chain motion is available to permit unconditional operation of derailleurs, is used to place the powered shifter mechanism in an optimal position on a consistent basis in order to provide a more pleasurable and comfortable experience for the rider thereby consistently achieving acceptable pedaling rates and efforts based on the ever changing need of the rider.